When a XSK pool gets mapped, xp_check_dma_contiguity() adds bit 0x1
to pages' DMA addresses that go in ascending order and at 4K stride.
The problem is that the bit does not get cleared before doing unmap.
As a result, a lot of warnings from iommu_dma_unmap_page() are seen
in dmesg, which indicates that lookups by iommu_iova_to_phys() fail.
Fixes: 2b43470add8c ("xsk: Introduce AF_XDP buffer allocation API")
Signed-off-by: Ivan Malov <ivan.malov@xxxxxxxxxxxx>
---
v1 -> v2: minor adjustments to dispose of the "Fixes:" tag warning
v2 -> v3: extra refinements to apply notes from Magnus Karlsson
net/xdp/xsk_buff_pool.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 87bdd71c7bb6..f70112176b7c 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -332,6 +332,7 @@ static void __xp_dma_unmap(struct xsk_dma_map *dma_map, unsigned long attrs)
for (i = 0; i < dma_map->dma_pages_cnt; i++) {
dma = &dma_map->dma_pages[i];
if (*dma) {
+ *dma &= ~XSK_NEXT_PG_CONTIG_MASK;
dma_unmap_page_attrs(dma_map->dev, *dma, PAGE_SIZE,
DMA_BIDIRECTIONAL, attrs);
*dma = 0;
--
2.30.2
